There are several variations of this technique, but afaics they all have a problem shots exactly from the side, where you can only see the lense, not the iris. Never saw such an effect on photos or in real life.
So am I missing something? Is there a trick to handle side views?
http://www.polychondritis.com/Anatomy/EyeAnatomy.html
Geometry that more closely matches the actual anatomy would likely have the same problem, although to a lesser extent, as how it looks from the outside has probably a lot to do with fluids.
Does anyone know of good looking approaches with no inward bend of the iris? Good looking from all angles, that is. And then I’m trying to avoid raytracing for my current project …
Good point. The Pixar eye is designed to get the highlights on the cornea and the catchlight on the iris. I wonder if it’s possible to fake an iris side view by using a color map on the cornea set to normal so it would only be visible in exact side views?
My first thought would be to see if I could pouf the iris out a little beneath the cornea, so some of the color shows up even in a side view, and see if I can do it without screwing up the look from the front.
Second thought would be to wonder if I could set a material on the back side of the cornea only, maybe make it an enviromap to reflect the iris color. Heck, you might be able to do a full enviromap on the cornea from a layer with nothing but the iris and cornea, because then most of it will just be transparent, right?
Orinoco: I thought about the same lines, but don’t know if it is possible at all. Plus, what about non-exact side views?
Ammusionist: It just doesn’t work in side view. What would the variation be?
Star Weaver: Interesting idea. I will try that.
If it doesn’t work out, I’ll just model a more or less anatomically correct eye to see whether the catchlight effect is that important or if it can be faked with a ramp perhaps.
Problem is the catchlight is supposed to show up on the opposite side of the circle as the highlight. If the cornea and the iris have the same curve, the reflections show up in the same place.
A slightly outward bend iris with a fresnel shader seems to work quite nice. Don’t know what to do regarding texturing yet. Perhaps just alpha blending 2 or more materials.
Is there any way to make the backsides of single-sided faces invisible on rendering?
This is a sphere with the front pulled out for the cornea. Iris and pupil are not connected but part of the same mesh. Iris is bent outwards and the pupil is pushed back, building a cylinder. This is done to avoid it looking like a black spot floating on the iris.
I think I once saw a photo with an eye from the side where one could see the cornea as lense with some thickness. But I didn’t find any nice reference shots now. Asked my brother to pose as model. It was terrible hard to understand what I saw and he couldn’t stand the situation for more than like 2 seconds, so I’m none the wiser. Don’t have a digi-cam.
Failed to find a way to make faces invisible from the non normal facing side. I wanted to ‘fill’ the cornea this way.
For some reason, the cornea stood out in the render, but was barely visible on the saved image (with alpha). Fixed this by copieng the layer several times. Wonder what’s going on there, though.
The white material looks rather stupid here, but works ok with the eyeballs ‘embedded’ in a face. Don’t want harsh shadows there.
Iris has a fresnel material. I will try using a UV texture to blend 2 fresnel materials later on.
sorry to say but these eyes look more cartoonish than pixar. i think you need harder materials. cant you set the alpha value to get the clear look? I did a pair of pixar eyes a while back. ill upload them on to this page when i get home from work today.
Well, how could they look realistic without any texture and a toon material for the eyeball? The whole point was having the iris brighter on the opposite side of the highlight and visible from the side.
Should have mentioned that this eyeball is for/from a stylized character, though.
Which is not to say it would look convincing in any way right now
It would be great if someone with a digicam could post shots of eyes exactly from the side.
I’m a noob but then again ill try not to look too stupid.
i once tried to put ray transparency with a high IOR. so when i rendered it in a side view it didn’t show off the concave iris, because it refracted it a lot
The cornea sticking out a bit is part of most eye modeling tutorials. It sticks out in my geometry, too, but perhaps not enough.
I just tried viewing my own eye from the side using 2 mirrors. From most angles, you can see at least a bit of colour from the iris. It appears much brighter from the side.
